Plasma tube additives

Whole blood/plasma tubes K2EDTA (dry additive) K3EDTA (liquid additive) Na2EDTA (dry additive) Lavender Lavender... 

Fibrin clots in plasma from overfilling interference of tube additive in test method hemolysis fiom underfilfing Assay interference hemolysate contains biomarker or releases intracellular proteases that degrade the biomarker Assay interference... 

Graphite was tised as substrate for the deposition of carbon vapor. Prior to the tube and cone studies, this substrate was studied by us carefully by STM because it may exhibit anomalotis behavior w ith unusual periodic surface structures[9,10]. In particular, the cluster-substrate interaction w as investigated IJ. At low submonolayer coverages, small clusters and islands are observed. These tend to have linear struc-tures[12j. Much higher coverages are required for the synthesis of nanotubes and nanocones. In addition, the carbon vapor has to be very hot, typically >3000°C. We note that the production of nanotubes by arc discharge occurs also at an intense heat (of the plasma in the arc) of >3000°C. 

GC-AAS has found late acceptance because of the relatively low sensitivity of the flame graphite furnaces have also been proposed as detectors. The quartz tube atomiser (QTA) [186], in particular the version heated with a hydrogen-oxygen flame (QF), is particularly effective [187] and is used nowadays almost exclusively for GC-AAS. The major problem associated with coupling of GC with AAS is the limited volume of measurement solution that can be injected on to the column (about 100 xL). Virtually no GC-AAS applications have been reported. As for GC-plasma source techniques for element-selective detection, GC-ICP-MS and GC-MIP-AES dominate for organometallic analysis and are complementary to PDA, FTIR and MS analysis for structural elucidation of unknowns. Only a few industrial laboratories are active in this field for the purpose of polymer/additive analysis. GC-AES is generally the most helpful for the identification of additives on the basis of elemental detection, but applications are limited mainly to tin compounds as PVC stabilisers. 

Additionally, the inj ected matrix must also be miscible with the solvents used in the separations. For normal phase mode separations, all water must be removed from the injected matrix. Since many of the complex matrixes, such as plasma, urine, and other biological fluids contain a large amount of water, this requires more time consuming sample preparation. However, water can be injected into a polar organic or reverse phase mode separation. Even within the same mode, mobile phases that are very different can cause large disturbances in the baseline. Oda et al., (1991) solved this problem by inserting a dilution tube followed by a trap column in order to dilute the mobile phase used on the achiral column. Following the dilution tube, a trap column was used to reconcentrate the analyte of interest before the enantiomeric separation. 

Glucagon is extensively degraded in the liver and kidney as well as in plasma and at its tissue receptor sites. Because of its rapid inactivation by plasma, chilling of the collecting tubes and addition of inhibitors of proteolytic enzymes are necessary when samples of blood are collected for immunoassay of circulating glucagon. Its half-life in plasma is between 3 and 6 minutes, which is similar to that of insulin. 

The reduction reaction is carried out in 1.5-ml Eppendorf tubes. Frozen samples are thawed out, thoroughly mixed and, if necessary, centrifuged to remove particulate material. For samples and the pooled plasma blank, 150 pi plasma and 50 pi internal standard in 0.1 mol/1 borate buffer are added to 20 pi of 10% tri-n-butylphosphine. For each Hey standard, 150 pi of pooled plasma and 50 pi of Hey standard (internal standard is included) are mixed with 20 pi of tri-n-butylphosphine. Tubes are left to stand on ice for 30 min. Samples are deproteinised by the addition of 125 pi of... 

Samples of 50 pi plasma, standard or control plasma, 20 pi internal standard and 10 pi dithiothreitol solution are thoroughly mixed (vortex) in 1-ml Eppendorf tubes. The tubes are left to stand at room temperature for 15 min. Samples are then depro-teinised by the addition of 500 pi deproteinising acetonitrile solution, with thorough vortex mixing followed by centrifugation at 14,000 rpm (11,000 x g) for 5 min (4°C). Tandem mass spectrometry analysis is performed on 200 pi of the supernatant reserved in appropriate vials. If the analysis is not performed immediately, samples can be stored at -20°C until analysis. 

Frozen deproteinised samples are thawed out, thoroughly mixed and then centrifuged at 2000 xg for 5 min at 4°C. If the supernatant is turbid it should be clarified by filtration as described earlier. Derivatisation is performed in 5-ml Pyrex tubes. For plasma samples, 200 pi supernatant is added to 50 pi chloracetaldehyde and thoroughly mixed, followed by addition of 45 pi of 3 mol/1 sodium acetate to ad-... 

Prepare 5-ml plastic tubes in duplicate for each assay condition (background, reaction with 1 xS, reaction with 10 xS, standard), that is eight tubes for each plasma sample (include one control plasma as quality control for each assay set), and four additional tubes for each assay set as shown in Table 3.7.1. 

The vapor can be atomized in inert gas-hydrogen diffusion flames, in narrow-bore quartz tubes electrically heated or heated over an air-acetylene flame, and in plasmas. Additionally, the atomizer can act as a vapor preconcentration medium just before atomizing. This is what happens in graphite furnace atomizers (in situ trapping) or on silver or gold wires for direct amalgamation of mercury. 

Initially, plasma and oral fluid specimens from patients (n = 21) on different antidepressant treatment were collected twice to assess if any of the studied analytes was likely to show a good correlation. The best results were obtained for venlafaxine (%CV for plasma/oral fluid concentrations ratio (f OF/PL) <21%). Therefore, the study was extended for this antidepressant by analysis of oral fluid and plasma specimens from five patients on venlafaxine treatment collected on four occasions. Daily doses of venlafaxine retard formulations were 75 mg for two patients, and 150 mg for the remaining participants. Collection of oral fluid (direct spitting into polypropylene tubes) and plasma (heparinized tubes) specimens was performed, when possible, before the next dose to ensure the drug was in the elimination phase. The dose and the time of collection was the same on the four different occasions for each patient. For the analysis, oral fluid and plasma specimens were centrifuged at 14 x 103 rpm, and 0.2 mL of the supernatant were extracted. In addition, correlation between the concentrations in the plasmatic free fraction and in oral fluid was also evaluated. Plasmatic proteins were eliminated by filtering 0.5 mL of plasma samples using Microcon filter devices Ultracel YM-3 (Millipore Corp., Billerica, MA, USA). 

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